The IASP Classification of Chronic Pain for ICD-11: Chronic Primary Pain

Michael Nicholas; Johan W.S. Vlaeyen; Winfried Rief; Antonia Barke; Qasim Aziz; Rafael Benoliel; Milton Cohen; Stefan Evers; Maria Adele Giamberardino; Andreas Goebel; Beatrice Korwisi; Serge Perrot; Peter Svensson; Shuu-Jiun Wang; Rolf-Detlef Treede; The IASP Taskforce for the Classification of Chronic Pain


Pain. 2019;160(1):83-87. 

In This Article

Background on Chronic Primary Pain

There are 2 main diagnostic classification systems used internationally for chronic pain, apart from headaches: the Diagnostic and Statistical Manual (DSM) published by the American Psychiatric Association (APA), and the International Classification of Diseases (ICD) published by the World Health Organization (WHO). However, both have been found wanting in their accounts of chronic pain conditions. In particular, neither system reflects the developments in pain research over the last 2 decades, and they do not have clear treatment or management implications.[10,15,16,38,61] To illustrate, ICD-10 refers to pain attributable exclusively to an underlying pathophysiological mechanism.[19] In the absence of a clear (pathophysiological) etiology, and when biological, psychological, and social factors seem to be contributing to a chronic pain presentation,[15]ICD-10 offers only the option of "somatoform pain disorder." However, this classification cannot be used when pathophysiological factors are also considered to be contributing to the pain problem.[39]

These distinctions have important treatment implications. As Taylor and colleagues pointed out, if we accept that chronic pain is a disease or a long-term condition, "then the philosophy of care may change from a biomedical model that views chronic pain as a symptom to that of a biopsychosocial one that views chronic pain as a disease or long-term condition" (p. 1948).[53] In an attempt to address the problems with the representation of chronic pain in ICD, the German adaptation of ICD-10 (ICD-10-GM) introduced the concept of "chronic pain disorder with somatic and psychological factors."[18] It was an important step to acknowledge equal contributions of somatic and psychological factors, and the concept seems well-accepted. However, not only is this diagnosis limited to German-language countries, it still rests in the psychiatric section of the classification. Conceptually and clinically, it seems overly broad: it can be applied to most chronic pain conditions and fails to recognize subtypes. In this article, the suggested concept of chronic primary pain (CPP) overcomes these limitations by providing a clear definition unencumbered by inappropriate classification within psychiatric disorders, and it allows for subtypes. The challenge to conceptualize chronic pain as a long-term condition has been accentuated by advances in the understanding of psychological, social, and central nervous system mechanisms that may account for many hitherto inexplicable pain phenomena.[37,51,60,61] These developments have meant that attempts to classify chronic pain presentations need to acknowledge the likelihood of multiple interacting contributors to a chronic pain presentation. The alternative of pain being either "somatic" or "psychogenic" has become obsolete in several ways. Psychological factors such as learning and coping play a role in chronic pain that was previously considered "somatic," eg, chronic osteoarthritis (now classified as one of the "chronic secondary pain syndromes"). Vice versa, biological changes are closely linked to psychological processes; this is most obvious in neurophysiological brain reactions contributing to changes in pain perception. As will become apparent, these developments are acknowledged by the new diagnostic entity of CPP. The new entity will also provide a framework to unite conditions that have hitherto been scattered throughout the ICD and help to focus on their commonalities and differences.